Experiments are proposed in which the mechanism of delta 9-THC's enhancement of monosynaptic CA-1 field potentials in the intact dorsal hippocampus of rats will be investigated. Other studies will use the hippocampal explant technique in an attempt to confirm prior results for delta 9-THC and lamellar potentials and to provide an anesthetic-free system for further studies of delta 9-THC and hippocampal physiology. A treadmill will be used to study effects of delta 9-THC on movement-triggered hippocampal theta activity in unrestrained rats. Manipulations of 5-HT and GABA levels in the brain will aid in identifying the mechanism of cannabis action on theta patterns. Systemic administration of scopolamine or physostigmine in combination with delta 9-THC will allow assessment of the latter drug's effects on cholinergic pathways in the septal-hippocampal theta system. Effects of delta 9-THC on food intake and body weight will be observed under conditions of caloric dilution and altered palatability of the diet. Hypothalamic mechanisms of food intake regulation will be investigated with respect to possible influences of delta 9-THC.